Electrode for searchlights and method of making the same



E. A. SPERRY.

ELECTRODE F011 SEARCHLIGHTS AND METHOD OF MAKING THE SAME. APPHCATIION FILED JULY 15, 1916.

1.2 Fig. 5.

l/VVE/VTOR ELMEH A. SPEHRX Patented June 1,1920.

UNITED: STATES PATENT OFFICE.

ELMER a SPERRY, or BRooxLYa NEW YORK.

ELECTRODE FOR SEARCHLIGHTS AND METHOD OF MAKING THE SAME.

Application flled J'uly 15, 1916. Seria1 N9. 109, 564.

T0 all whom it may concern Be it known that I, ELMER A. SPERRY,a

"citizen of the United States, residing at .1505 Albermarle road, Brooklyn, in the county of Kings and btate of NewYork,

have'invented certain new and useful Improvements in Electrodes for Searchlights and Methods of Making the Same, of which the following is a specification.

This invention relates to improvements in carbon electrodes for are lights, relatin especially to cored flaming arc carbons, an it has for its object a number of substantial improvements in' these carbons, whereby,

amon other objects, the steadiness. and reliability of the light are improved.

The invention consists in providing means whereby the core and shell or the blow out a piece of the core.

complete cored electrode may be baked but isnotnecessarily In the finished product, however, the core is not simultaneously,

only firmly located in the shell by having ri d contact, but this contact or contact su stance is rendered porous or of such a character that gas may be passed longitudinally of the electrode, preferably between the core and the shell.

In cored are light electrodes for the modern high intensity searchlights, difliculty has been ex erienced in keeping the core in place. Owm

timate contact between the core and the shell it frequently happens that arcing takes place between and wlthin the shell and core causing gases to be formed therein which This generally renders it necessary to shut down the light, as the protruding core will touch the other electrode and form a short circuit between the two. I, therefore, propose to provide "means not only to lock the shell and core firmly to ether, but to permit the escape of any gas t at may be formed therebetween.

' In attaining these objects,.I may employ various means either separately or conjointly. Prominent among these is to provide'in the hole within the shell irregularities at different} points axially. consist of undulations. They may be spiral or .of any confi uration, but it is preferable that they shoul eventually progress axially,

to the high current density. employed an the difficulty in securing inhese may aiding in the egress of anygas oivolatile matter evolved under conditions of the in-' Specification of Letters Patent. Patented June 1, 1920.

in aidingthe same phenomena during the baking or curing of the carbon prior to its use.

Referringto the drawings, which show".

some forms of my invention, Figure 1 is a longitudinal section of finished carbon made according to my invention. Y

Fig. 2 is a corresponding section of a modified form of shell. a Fig. 3 shows. another modification.

Fig. 4 is a cross section thereof.- Fig. 5 is a diagrammatic sectional view of the container used during the extruding.

process.

Fig. 6 is a section of a form that may be employed during the process of uniting the shell and core. Y

According to this invention, the first step in manufacturing the shell-1 and the core- 2 are performed in the usual manner by separately extruding or squirting the carbonaceous material while in a pasty or plastic state. Such an apparatus is illustrated in Fig. 5, in which 19 is a container for the carbonaceous 'mass, 11 a hole therein through which the mass is extruded and 12 a plug to form the axial bore 6 of the shell.

Preferably I incorporate in the core not only the usual carbonaceous material with an agglutinous binder, and flamlng arc salts, but also a sufficient amount ,of tar or other spongy substance to be exuded dur ing the subsequent curing and baking processes for forming a porouslayer or binder 3 between the core and the shell. The shell may also be provided with volatile salts, if desired.

shell may be formed during the squirting process by making the plug 12 of irregular sha e and slowly revolving it. A pulley 13 is shown as mounted on' the shaft 14. of

however, as the undulations may be forme' by imparting lateral movement to the plug, or they may be formed after the squirting The undulations 5 in the bore 6 of the v proces'sflby running a roughening or cutting I tool, 15 into the bore, forming incisions therein. Still another method is toapply pressure to the shell at predetermined points, Whilethe shell is plastic. Also, as above stated, the undulations may be of any configuration, but preferably progress axi-,

ally. In Fig. 1, they areshown as waves,

while in Fig. 2 they appear as of spiralconfiguration. In Fig. 3, spaced annular depressions, 16 are formed, preferably connected by an axial groove 17. After the bore is properly formed; it may be lubricated by a li uid containing volatile matthe core from the mold directly into the shell. The shell may be incased by tubing 18 at the time of receiving the 'core to prevent its bursting and alSO to provide an abutment or stop 20 against which the coilemay 'be pressed. The core is forced within the shell until it strikes the said abutment. Pressure may then be continued to be ap plied thereto to expand it within the shell so as to partially fill the undulations in the bore. The core is then cured within the shell by, gentle heat, during which the exudations from the core or from the,coreand shell leave a spongy mass of carbonaceous material between the core and the shell, which serves to at least partially fill the undulations and lock the core and shell' together.

The electrodes are then ready for the baking process, during which it is gradually raised to a very high temperature. They are preferably heated in a ventilated chamber of porous material in contact with the walls thereof to prevent deformation.

The electrodes are also shielded fromoxidation and their ends vented to permit the escape of the volatile matter exuded therefrom. During this process, a further exudation of tarry} matter takes place, all

-of which, including the spongy binder-between the core and shell, is evaporated,

leaving a. porous binder 3- between the core and shell. Such a binder not only unites the core and shell firmly, but also permits M the escape ofany gas that-may be formed I during the burning of the-arc, between the core and shell[ This last featnre is of especial importance inhigh intensity are llghts employing from 150 to 200 'amperes,

as frequently arcing takes place in this type of li ht between and within the shell andcore, orming gas which, if not allowed i to escape will blow out apiece of the core,

as explained above,

Having described my invention, what I claim and desire to secure by. Let ers Patent is 1. A carbonaceous electrode comprising a. shell provided with an axial aperture having an undulatory surface, a core withinsaid aperture, and means for uniting the core and shell.

2. A carbonaceous electrode comprising a shell provided with an axial aperture havin sald aperture, and means for interlocking said core with said undulations.

3. A carbonaceous electrode comprising a an undulatory surface, a core within.

shell provided with an axial aperture, a"

core of a vcomposition different from that of saidshell within saidaperture and means for permitting the axial escape of gas formed wit-hinthe electrode. 7

4'. A carbonaceous electrode comprising a shell provided with an axial aperture having radial depressions, a core within said aperture, and a binder between said core and shell.

5. A carbonaceous electrode comprising a shell provided with an axial aperture, a core within said aperture, and a layer located between the core and the shell. j." v

6. A carbonaceous electrode comprising a. shell provided'with an axial aperturehaving an undulatory surface. a core within said aperture,and means for causing said core to interlock with but only partially fill said undulations.

porous 7. The process of manufacturing arc I light electrodes which consists in molding the shell with an axial bore provided with undulations,-molding the core, fitting in the core, and causing the core to interlock with theundulations.

8. The; process of manufacturing arc light electrodes, which consists in molding the shell. with an axial bore provided with undulations, molding the core', then while in a plastic state, expanding the'corev with in the .bore and baklng theshell and core together;

9. The process light electrodes which consistsiin' molding of manufacturing. arc

the shell with an axialibofe making a core terial for rendering said core'-"plastic, in-' troducing such core within the shell while in its plastic state, and subjecting said core and shell to heat.

A 10,. The; process of" manufacturing arc flight'eleotrodes which consists in molding,

a shell with an axial bore having radial de,-.

containing carbon depositing volatile mapressions, directly extruding into such borefrom its mold a carbonaceous core while in its plastic state.

11. The process of manufacturing are light electrodes which consists in providing theshell with an axial bore having radial depressions, and directly extruding into such bore a carbonaceous core, While in a hot and plastic state.

'12. The process of manufacturing are light electrodes, which consists in molding the shell with an axial bore, making a core containing carbon producing volatile material for rendering said core plastic and extruding said core directly, while at an elevated temperature into the shell in' the plastic state, and subjecting said core and said shell to heat. a

13. The process of manufacturing are light electrodes which consists in molding a shell with an axial bore, directl extruding intosuch bore from its mo (1 a carbonaceous core while in its plastic state alllicil then expanding the .core within the s e In testimony whereof I have aflixed my signature. v

ELMER A. SPERRY. 

